/Engine/Source/Runtime/Engine/Classes/Sound/SoundWave.h
This is only used for DTYPE_Procedural audio. It's recommended to useUSynthComponentbase class for procedurally generated sound vs overriding this function. If a new component is not feasible, consider usingUSoundWaveProceduralbase class vsUSoundWavebase class since as it implements GeneratePCMData for you and you only need to return PCM data.
virtual int32 GeneratePCMData ( uint8 * PCMData, const int32 SamplesNeeded )